JP2009148979A - Laser exposure apparatus and image forming apparatus - Google Patents

Abstract

An object of the present invention is to prevent contamination of an irradiation window without increasing the size of the apparatus and to facilitate cleaning of the irradiation window.
An upper cover 216 including an irradiation window 212 is slidably attached to a casing 211 of the laser exposure apparatus. When exposing an external photoconductor, the irradiation window 212 is positioned on the optical path of the light beam emitted from the cylindrical lens 203 and allows the light beam to pass outside. In the illustrated standby position, the irradiation window 212 is located at a position off the optical path. During standby, the cleaning brush 215 is in contact with the outer surface of the irradiation window 212. The cleaning brush 215 is held by the guide rail 214 and can be moved in the main scanning direction. An operator or the like moves the cleaning brush 215 along the guide rail 214 so that the cleaning brush 215 can be slid with respect to the irradiation window 212 to be cleaned.
[Selection] Figure 3

Description

  The present invention relates to a laser exposure apparatus and an image forming apparatus, and more particularly, to a laser exposure apparatus applicable to an electrophotographic image forming apparatus such as a digital copying machine, a printer, and a facsimile, and the laser exposure apparatus. The present invention relates to an image forming apparatus.

  Image forming apparatuses such as digital copying machines, laser printers, and facsimiles have become widespread. In such an image forming apparatus, an image writing apparatus that scans a laser beam and writes an image on a photosensitive member is used. When an image is formed by the image forming apparatus, the photosensitive member is charged by the charging device and then written according to the image information by the image writing device to form an electrostatic latent image on the photosensitive member. Then, the electrostatic latent image on the photoreceptor is visualized with toner supplied from the developing device. The toner image visualized on the photosensitive member is transferred onto a recording sheet by a transfer device, and further fixed on the recording sheet by a fixing device, whereby a desired image can be obtained.

  In color image forming apparatuses such as digital copying machines and laser printers, a tandem system in which a plurality of photoconductors are arranged in tandem has been put into practical use as the speed thereof increases. Here, for example, four photosensitive drums are arranged in the conveyance direction of the recording paper, and these photosensitive members are simultaneously exposed by a scanning optical system corresponding to each of these photosensitive drums to form a latent image. The image is developed with a developing device using developers of different colors such as yellow (Y), magenta (M), cyan (C), and black (K). A color image is obtained by sequentially superposing and transferring these visualized toner images on the same recording paper.

In an electrophotographic image forming apparatus, a developer such as toner is generally used, and the toner falls or scatters in the image forming apparatus. For this reason, by using a laser exposure apparatus in which optical components for exposing the photosensitive member are arranged in the casing, these optical components can be shielded from toner and other dusts.
In such a laser exposure apparatus, optical components such as a laser diode and a polygon mirror are arranged in a casing, and a YDCK light beam is emitted from the casing to expose a photosensitive drum arranged outside the casing. I am doing so.

Accordingly, the casing of the laser exposure apparatus is provided with a light-transmitting irradiation window for allowing the laser beam to be emitted to the outside to pass, and the inside of the casing is also closed at the laser beam emission path portion. Yes.
However, since the outside of the irradiation window is also exposed to the environment where the toner falls, the toner adheres to the outer surface of the irradiation window and is contaminated, and the light beam transmission is reduced. There arises a problem that the quality of the formed image is lowered.

For example, Patent Document 1 discloses an apparatus provided with a shutter so as to prevent the irradiation window from being contaminated with toner or the like. Here, a covering member is provided which can be moved to a covering position for covering the light-transmitting dustproof member for closing the opening formed in the optical housing and an open position for opening the covering of the light-transmitting dustproof member. Further, a cleaning member that is in sliding contact with the outer peripheral surface of the translucent dustproof member when the covering member is moved is attached to the covering member. The covering member is moved before and after the start of the image forming operation, and the dust attached to the outer peripheral surface of the translucent dustproof member is automatically cleaned by the cleaning member.
JP 2005-329622 A

  As described above, when the outer surface of the light-transmitting irradiation window provided in the housing of the laser exposure apparatus is contaminated, there is a problem that the light beam transmission is lowered and the quality of an image formed is lowered. In order to solve this problem, a device that makes it difficult to attach toner or the like to the outer surface of the irradiation window and that can be quickly cleaned when it adheres is desired. At this time, due to the demand for downsizing of the image forming apparatus, a configuration that prevents the irradiation window from being soiled and can be cleaned without increasing the size of the apparatus is required.

  On the other hand, in the configuration of Patent Document 1, the thickness of the laser exposure apparatus is increased by providing a shutter, which causes a problem in miniaturizing the apparatus.

  The present invention has been made in view of the above circumstances, and a laser exposure apparatus capable of preventing contamination of an irradiation window and making the irradiation window easy to clean without increasing the size of the apparatus, and its laser An object of the present invention is to provide an image forming apparatus provided with an exposure apparatus.

  In order to solve the above-described problems, a first technical means of the present invention includes a laser emitting unit that emits laser light, and a photoconductor by scanning the laser light emitted from the laser emitting unit and exposing an external photoconductor. In a laser exposure apparatus that writes a latent image on, a housing having optical components of the laser exposure apparatus disposed therein and a cover that is attached to the housing and shields the optical components disposed inside the housing from outside air are provided. The cover has an irradiation window that transmits the laser beam to be emitted to the outside, and moves between an exposure position that transmits the laser beam through the irradiation window and emits the laser beam to an outside, and a standby position that blocks the optical path of the laser beam. It is characterized by being possible.

  The second technical means is the same as the first technical means, characterized in that the cover has a plurality of irradiation windows.

  According to a third technical means, in the first or second technical means, the cover is a shield that prevents toner for visualizing a latent image written on the photosensitive member from moving to the irradiation window in the vicinity of the irradiation window. A projection is provided.

  According to a fourth technical means, in the first technical means, a cleaning member for cleaning the irradiation window is provided in the vicinity of the irradiation window.

  A fifth technical means includes any one of the first to fourth technical means and a photoconductor, and forms a latent image on the photoconductor by a laser exposure device, and forms the latent image to form an image. It is characterized by doing.

  A sixth technical means includes a moving part for moving the cover and a control part for controlling the moving part in the fifth technical means, and the control part energizes the moving part during the image forming operation, and the cover Is moved from the standby position to the exposure position.

  A seventh technical means is the fifth technical means characterized in that the cleaning member contacts the irradiation window at the standby position.

  An eighth technical means is the seventh technical means characterized in that the cleaning member is slidably held by the irradiation window at the standby position.

  According to a ninth technical means, in the fifth technical means, a part of the housing of the image forming apparatus is configured to be openable and closable, and the opening and closing of the part of the housing of the image forming apparatus is interlocked with the movement of the cover. It is characterized by having a mechanism.

  According to the present invention, there is provided a laser exposure apparatus capable of preventing the irradiation window from being soiled and making the irradiation window easy to clean without increasing the size of the apparatus, and an image forming apparatus including the laser exposure apparatus. Can be provided.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration example of an image forming apparatus including a laser exposure apparatus according to the present invention. The image forming apparatus 100 forms multi-color and single-color images on a predetermined sheet (recording paper) according to image data transmitted from the outside. It is comprised by. The apparatus main body 110 includes an exposure unit 1, a developing device 2, a photosensitive drum 3, a cleaner unit 4, a charger 5, an intermediate transfer belt unit 6, a fixing unit 7, a paper feed cassette 81, a paper discharge tray 91, and the like. It is configured.

  A document placing table 92 made of transparent glass on which a document is placed is provided on the upper portion of the apparatus main body 110, and an automatic document processing device 120 is attached to the upper side of the document placing table 92. The automatic document processing device 120 automatically conveys the document on the document placing table 92. The automatic document processing device 120 is configured to be rotatable in the direction of arrow M, and the document can be manually placed by opening the document table 92.

  The image data handled in this image forming apparatus corresponds to a color image using each color of black (K), cyan (C), magenta (M), and yellow (Y). Accordingly, four developing devices 2, photosensitive drums 3, charging devices 5, and cleaner units 4 are provided to form four types of latent images corresponding to the respective colors, and are respectively provided in black, cyan, magenta, and yellow. These are set to form four image stations.

  The charger 5 is a charging means for uniformly charging the surface of the photosensitive drum 3 to a predetermined potential. In addition to the charger type as shown in FIG. 1, a contact type roller type or brush type charger is used. Sometimes used.

  The exposure unit 1 corresponds to a laser exposure apparatus according to the present invention, and is configured as a laser scanning unit (LSU) provided with a laser emitting portion, a reflection mirror, and the like. The exposure unit 1 includes a polygon mirror that scans a laser beam and optical components such as a lens and a mirror that guide the laser light reflected by the polygon mirror to the photosensitive drum 3. As the exposure unit 1, for example, a technique using an EL or LED writing head in which other light emitting elements are arranged in an array can be employed.

  The exposure unit 1 has a function of forming an electrostatic latent image corresponding to the image data on the surface thereof by exposing the charged photosensitive drum 3 according to the input image data. The developing unit 2 visualizes the electrostatic latent images formed on the respective photosensitive drums 3 with toner of four colors (YMCK). The cleaner unit 4 removes and collects toner remaining on the surface of the photosensitive drum 3 after development and image transfer.

  The intermediate transfer belt unit 6 disposed above the photosensitive drum 3 includes an intermediate transfer belt 61, an intermediate transfer belt driving roller 62, an intermediate transfer belt driven roller 63, an intermediate transfer roller 64, and an intermediate transfer belt cleaning unit 65. I have. Four intermediate transfer rollers 64 are provided corresponding to each color for YMCK.

  The intermediate transfer belt driving roller 62, the intermediate transfer belt driven roller 63, and the intermediate transfer roller 64 are driven to rotate while the intermediate transfer belt 61 is stretched. Each intermediate transfer roller 64 provides a transfer bias for transferring the toner image on the photosensitive drum 3 onto the intermediate transfer belt 61.

  The intermediate transfer belt 61 is provided so as to be in contact with each photoconductor drum 3, and the toner images of the respective colors formed on the photoconductor drum 3 are sequentially transferred to the intermediate transfer belt 61 and transferred. Further, it has a function of forming a color toner image (multicolor toner image) on the intermediate transfer belt 61. The intermediate transfer belt 61 is formed in an endless shape using, for example, a film having a thickness of about 100 μm to 150 μm.

  Transfer of the toner image from the photosensitive drum 3 to the intermediate transfer belt 61 is performed by an intermediate transfer roller 64 that is in contact with the back side of the intermediate transfer belt 61. A high-voltage transfer bias (a high voltage having a polarity (+) opposite to the toner charging polarity (−)) is applied to the intermediate transfer roller 64 in order to transfer the toner image. The intermediate transfer roller 64 is a roller whose base is a metal (for example, stainless steel) shaft having a diameter of 8 to 10 mm and whose surface is covered with a conductive elastic material (for example, EPDM, urethane foam, or the like). With this conductive elastic material, a high voltage can be uniformly applied to the intermediate transfer belt 61. In this embodiment, a roller shape is used as the transfer electrode, but a brush or the like can also be used.

  As described above, the electrostatic images visualized on the respective photosensitive drums 3 according to the respective hues are stacked on the intermediate transfer belt 61. As described above, the laminated image information is transferred onto the sheet by the transfer roller 10 disposed at a contact position between the sheet and the intermediate transfer belt 61 described later by the rotation of the intermediate transfer belt 61.

  At this time, the intermediate transfer belt 61 and the transfer roller 10 are pressed against each other at a predetermined nip, and a voltage for transferring the toner onto the sheet is applied to the transfer roller 10 (the polarity opposite to the toner charging polarity (−)). (+) High voltage). Further, in order to obtain the nip constantly, the transfer roller 10 uses either the transfer roller 10 or the intermediate transfer belt drive roller 62 as a hard material (metal or the like), and the other as a soft material (elasticity such as an elastic roller). A rubber roller, a foaming resin roller, or the like) is used.

  Further, as described above, the toner attached to the intermediate transfer belt 61 by contacting the photosensitive drum 3 or the toner remaining on the intermediate transfer belt 61 without being transferred onto the sheet by the transfer roller 10 is used in the next step. Therefore, the intermediate transfer belt cleaning unit 65 is configured to remove and collect the toner. The intermediate transfer belt cleaning unit 65 includes a cleaning blade as a cleaning member that comes into contact with the intermediate transfer belt 61. The intermediate transfer belt 61 that comes into contact with the cleaning blade is supported by an intermediate transfer belt driven roller 63 from the back side. ing.

  The paper feed cassette 81 is a tray for storing sheets (recording paper) used for image formation, and is provided below the exposure unit 1 of the apparatus main body 110. A sheet used for image formation can also be placed in the manual paper feed cassette 82. A paper discharge tray 91 provided above the apparatus main body 110 is a tray for collecting printed sheets face down.

  In addition, the apparatus main body 110 is provided with a substantially vertical sheet conveyance path S for feeding the sheets of the sheet feeding cassette 81 and the manual sheet feeding cassette 82 to the sheet discharge tray 91 via the transfer roller 10 and the fixing unit 7. It has been. In the vicinity of the paper transport path S from the paper feed cassette 81 or the manual paper feed cassette 82 to the paper discharge tray 91, pickup rollers 11a and 11b, a plurality of transport rollers 12a to 12d, a registration roller 13, a transfer roller 10, and a fixing unit. 7 etc. are arranged.

  The conveyance rollers 12 a to 12 d are small rollers for promoting and assisting conveyance of the sheet, and a plurality of conveyance rollers 12 a to 12 d are provided along the sheet conveyance path S. The pickup roller 11 a is provided near the end of the paper feed cassette 81, picks up sheets one by one from the paper feed cassette 81, and supplies them to the paper transport path S. Similarly, the pickup roller 11 b is provided near the end of the manual paper feed cassette 82, picks up one sheet at a time from the manual paper feed cassette 82, and supplies it to the paper transport path S.

  Further, the registration roller 13 temporarily holds the sheet being conveyed through the sheet conveyance path S. The sheet has a function of conveying the sheet to the transfer roller 10 at the timing when the leading edge of the toner image on the photosensitive drum 3 and the leading edge of the sheet are aligned.

  The fixing unit 7 includes a heat roller 71 and a pressure roller 72, and the heat roller 71 and the pressure roller 72 rotate with the sheet interposed therebetween. The heat roller 71 is set so as to reach a predetermined fixing temperature by a control unit based on a signal from a temperature detector (not shown), and the toner is thermocompression bonded to the sheet together with the pressure roller 72. It has the function of fusing, mixing, and pressing the transferred multicolor toner image and thermally fixing the sheet. Further, an external heating belt 73 for heating the heat roller 71 from the outside is provided.

  Next, the sheet conveyance path will be described in detail. As described above, the image forming apparatus is provided with the paper feed cassette 81 for storing sheets and the manual paper feed cassette 82 in advance. Pickup rollers 11a and 11b are arranged to feed sheets from the sheet feeding cassettes 81 and 82, respectively, and guide the sheets one by one to the conveyance path S.

  The sheet conveyed from each of the sheet feeding cassettes 81 and 82 is conveyed to the registration roller 13 by the conveying roller 12a in the sheet conveying path S, and the transfer roller is aligned at a timing when the leading edge of the sheet and the leading edge of the image information on the intermediate transfer belt 61 are aligned. 10 and image information is written on the sheet. Thereafter, the sheet passes through the fixing unit 7 so that the unfixed toner on the sheet is melted and fixed by heat, and then discharged onto the sheet discharge tray 91 through the conveying roller 12b disposed thereafter.

  The above-described conveyance path is used when a single-sided printing request is made on a sheet. On the other hand, when a double-sided printing request is made, the single-sided printing is finished and the trailing edge of the sheet that has passed through the fixing unit 7 is When the sheet is held by the final conveying roller 12b, the conveying roller 12b rotates backward to guide the sheet to the conveying rollers 12c and 12d. Then, after printing is performed on the back surface of the sheet through the registration roller 13, the sheet is discharged to the discharge tray 91.

  Next, the configuration of the exposure unit 1 provided in the image forming apparatus will be described more specifically. The exposure unit 1 simultaneously scans and exposes a plurality of photosensitive drums 3 with a plurality of light beams, writes images corresponding to different colors on the photosensitive drums 3, and writes the images corresponding to the respective colors on the same transfer medium. It is applied to the tandem type image forming apparatus as described above for forming a color image by superimposing on the image.

  As described above, the photosensitive drums 3 for K image formation, C image formation, M image formation, and Y image formation are arranged in the image forming apparatus at substantially equal intervals. The tandem image forming apparatus forms images of the respective colors at the same time, so that the time required for forming a color image can be greatly shortened.

  The exposure unit 1 for exposing the photosensitive drum 3 includes a unitary primary optical system (incident optical system) and a secondary optical system (exit optical system). The primary optical system includes four laser emitting units for emitting YMCK laser beams, and optical elements such as mirrors and lenses for guiding these laser beams to a polygon mirror (rotating polygon mirror) of the secondary optical system. I have. Further, the secondary optical system includes the polygon mirror that scans the laser beam on the photosensitive drum as the scanning target, and optical elements such as a lens and a mirror for guiding the laser beam reflected by the polygon mirror to the photosensitive drum. And a BD sensor for detecting laser light. The polygon mirror employs a configuration shared by each color.

  2 and 3 are diagrams showing a configuration example of the secondary optical system of the laser exposure apparatus, and schematically show the inside of the housing as seen from the side of the exposure unit of the secondary optical system. Here, FIG. 2 shows an exposure state (exposure position) when the laser beam is irradiated from the inside of the unit toward the photosensitive drum through the irradiation window (that is, during printing), and FIG. 3 shows the position of the irradiation window shifted. It shows a standby state (standby position) where the optical path of the light beam is blocked.

  2 and 3, 201 is a polygon mirror, 202 is an fθ lens, 203 is a cylindrical lens, 204 is a first mirror for Y, 205 is a second mirror for Y, 206 is a mirror for K, and 207 is a first mirror for C. Mirror, 208 second mirror for C, 209 first mirror for M, 210 second mirror for M, 211 a housing of the laser exposure unit, 212 an irradiation window, 213 a shielding protrusion, 214 a guide rail, 215 is a cleaning brush, 216 is an upper cover, 221 is a driver, 222 is a solenoid, 223 is a rotation fulcrum, 224 is a spring, and 225 is a rotation arm.

  The polygon mirror 201 has a plurality of (for example, seven) reflecting surfaces in the rotation direction, and is driven to rotate by a polygon motor (not shown). The polygon motor is installed in a recess on the back surface side of the casing 211 in which the polygon mirror 201 is installed, and a lid for sealing the recess is provided. A light beam of each color emitted from a laser diode of a primary optical system (not shown) and reflected by an optical system such as a mirror is reflected by a reflecting surface of a polygon mirror 201 of a secondary optical system, and each optical element such as a mirror thereafter. Then, the light passes through the irradiation window 212 and is emitted to the outside so that the photosensitive drum 3 can be scanned.

  The irradiation window 212 is made of a light-transmitting material such as glass. When the photosensitive drum 3 is exposed, the irradiation window 212 is positioned on the optical path of the light beam for exposing the photosensitive drum 3. It is located at a standby position outside the optical path of the light beam. The cleaning brush 215 is in contact with the irradiation window 212 at the standby position. The cleaning brush 215 is slidably held on the irradiation window 212. The movement of the irradiation window 212 and the mechanism of the cleaning brush 215 will be described later.

  KCMY laser light emitted from a laser diode of a primary optical system (not shown) is incident on the polygon mirror 201 with an angular difference in the sub-scanning direction. Then, these laser beams maintain an angular difference and are separated after passing through a scanning optical system by the fθ lens 202. The fθ lens 202 has lens power in the main scanning direction. Thereby, in the main scanning direction, the light beam of the parallel light emitted from the polygon mirror 201 is converged so as to have a predetermined beam diameter on the surface of the photosensitive drum 3. Further, the fθ lens 202 has a function of converting laser light that moves at a constant angular velocity in the main scanning direction by the constant angular velocity movement of the polygon mirror 201 so as to move at a constant linear velocity on the scanning line on the photosensitive drum 3. is doing.

  Of the four laser beams for each color of KCMY separated by the polygon mirror 201 and passing through the fθ lens 202, the Y laser beam (Y beam) is the first Y mirror 204 and the second Y mirror 205. And then passes through the irradiation window 212 of the upper cover 216 slidably installed on the upper portion of the housing 211 and enters the Y photosensitive drum 3. . Drawing is performed in the scanning area on the photosensitive drum 3.

The separated M laser light (M beam) passes through the fθ lens 202, is then reflected in turn by the first M mirror 209, and the second M mirror 210, and passes through the M cylindrical lens 203. Then, the light passes through the M irradiation window 212 and enters the M photosensitive drum 3.
Similarly, the separated C laser beam (C beam) passes through the fθ lens 202, and then is sequentially reflected by the first C mirror 207 and the second C mirror 208, and the C cylindrical lens 203. , Passes through the irradiation window 212 for C, and enters the photosensitive drum 3 for C. The K laser light (K beam) passes through the fθ lens 202, is reflected by the K mirror 206, passes through the K cylindrical lens 203, passes through the K irradiation window 212, and passes through the K irradiation window 212. Incident on the body drum 3.

  The laser light for each color emitted from each cylindrical lens 203 exposes each charged photosensitive drum 3 according to image data. Thereby, an electrostatic latent image corresponding to the image data is formed on the surface of each photosensitive drum 3. Then, the electrostatic latent images formed on the respective photosensitive drums 3 are visualized by the developing unit by the KCMY toner.

  The housing 211 blocks the optical components arranged inside from the outside air, and is shielded from the outside air by an upper cover 216 (corresponding to the cover of the present invention) covering the upper opening. The upper cover 216 is configured to be slidably attached to the casing 211. The sliding movement direction of the upper cover 216 coincides with the arrangement direction of the photosensitive drums 3 in this example. An irradiation window 212 for allowing each light beam that exposes each photosensitive drum 3 to pass is provided in the upper cover 216. In the tandem exposure unit 1 of this configuration, a plurality of irradiation windows 212 (four in this configuration) are provided on the upper cover 216.

  The slide operation of the upper cover 216 is executed by the solenoid 222, a transmission mechanism for the drive operation, and a driver 221 (control unit) that controls the solenoid 222. The solenoid 222 corresponds to the moving unit of the present invention. Here, the driver 221 controls the solenoid 222 according to the control signal received by the driver 221 to drive the solenoid 222. The drive shaft of the solenoid 222 is biased by the spring 224 in the direction in which the drive shaft is pulled out (left direction in the drawing). When the solenoid 222 is driven, the rotation arm 225 is rotated clockwise with the rotation fulcrum 223 as a rotation axis. As a result, the upper cover 216 slides relative to the casing 211.

In accordance with the sliding operation of the upper cover 216, the four irradiation windows 212 provided corresponding to the optical paths of the light beams for YMCK simultaneously move, and the exposure state of the photosensitive drum shown in FIG. The standby state shown in FIG. 3 can be taken.
Here, in the exposure state shown in FIG. 2, each irradiation window 212 is positioned on the optical path of each light beam for YMCK from the inside of the casing 211 toward the photosensitive drum 3 so that each light beam can pass therethrough. Yes. In the standby state shown in FIG. 3, each irradiation window 212 is positioned away from the light path of the light beam, and the light path of each light beam is shielded by the wall portion of the upper cover 216.

  A cleaning brush 215 that is a cleaning member is installed at a position facing each irradiation window 212 at the standby position shown in FIG. 3, and the cleaning brush 215 is in contact with the outer surface of the irradiation window 212. Each irradiation window 212 has an elongated shape in the main scanning direction (direction perpendicular to the paper surface of FIGS. 2 and 3) in accordance with the light beam scanned in the main scanning direction of the exposure unit 1. Accordingly, the cleaning brush 215 also has an elongated shape in the main scanning direction so that the irradiation window 212 elongated in the main scanning direction can be cleaned.

  A guide rail 214 that holds the cleaning brush 215 so as to be movable in the main scanning direction is provided, and an operator or the like moves the cleaning brush 215 along the guide rail 214 so that the cleaning brush 215 is moved with respect to the irradiation window 212. The entire irradiation window 212 can be cleaned. A shielding protrusion 213 for preventing toner from moving onto the irradiation window 212 is provided in the vicinity of the irradiation window 212 on the upper cover 216. With such a configuration, it is possible to clean dirt such as toner dropped on the irradiation window 212 from the photosensitive drum 3 side. Further, in a standby state where no exposure is performed, the upper cover 216 provided with the irradiation window 212 is in the standby position shown in FIG. 3, so that the toner falling from the photosensitive drum 3 side is difficult to adhere.

  As described above, the upper cover 216 is slid by the solenoid 222. When the solenoid 222 is off, the upper cover 216 is positioned at the standby position in FIG. 3, and when the solenoid is turned on, the upper cover 216 is moved. 216 moves to the exposure position of FIG. Therefore, the solenoid is off at the time of standby, and it is sufficient to energize the solenoid only when the photosensitive drum 3 is exposed at the exposure position (that is, at the time of printing), and the power consumption of the apparatus can be reduced. If the photosensitive drum 3 is not being exposed (that is, not being printed), the irradiation window can be cleaned at any time.

(Embodiment 2)
4 and 5 are diagrams showing another configuration example of the secondary optical system of the laser exposure apparatus, and schematically show the inside of the housing as seen from the side of the exposure unit of the secondary optical system. 4 shows an exposure state (exposure position) when laser light is irradiated from the inside of the unit toward the photosensitive drum through the irradiation window 212 (that is, during printing), and FIG. 5 shows the position of the irradiation window shifted. This shows a standby state (standby position) where the optical path of the light beam is blocked.

The image forming apparatus of the present embodiment has the same configuration as that of the embodiment of FIG. 1 described above, and can irradiate the photosensitive drum 3 with a KCMY light beam through the irradiation window 212 to form an image. In this embodiment, unlike the first embodiment, the upper cover 216 of the exposure unit 1 is not provided with the cleaning brush 215 and the guide rail 214 for guiding the cleaning brush 215.
Although the upper cover 216 is configured to be slidable, it is not driven in accordance with the operation of the solenoid 222 as in the first embodiment, and is a front surface provided in a casing constituting the image forming apparatus. An interlocking mechanism is provided in which the upper cover 216 slides in conjunction with opening and closing of the door. A projection 217 provided on the upper cover 216 is used for the interlocking mechanism. This interlocking mechanism will be described below. 4 and 5 are the same as the configurations of FIGS. 2 and 3 except for the portions that characterize the present embodiment, and the repeated description thereof is omitted.

FIG. 6 is another view showing an example of the configuration of an image forming apparatus provided with a laser exposure apparatus according to the present invention, and schematically shows the appearance of the image forming apparatus. In the figure, reference numeral 111 denotes a front door.
The image forming apparatus 100 is provided with a front door 111 for opening and closing a part of the casing. By opening the front door 111, the developing device 2, the photosensitive drum 3 and the like installed in the apparatus can be attached and detached. An operator or the like can open the front door 111 and insert a cleaning brush into the apparatus to clean the irradiation window.
That is, the front door 111 is opened when the developing device 2, the photosensitive drum 3 or the like is replaced. At this time, an interlocking mechanism for sliding the upper cover 216 in conjunction with the front door 111 is provided so that the irradiation window 212 is not contaminated by the toner falling when the developing device 2 or the photosensitive drum 3 is replaced. When the cover 111 is opened, the upper cover 216 is moved to the standby position.

  FIG. 7 is a schematic diagram for specifically explaining the configuration of the interlocking mechanism that slides the upper cover shown in FIGS. 4 and 5, and shows a state in which the moving plate provided in the image forming apparatus is viewed from above. It is. FIG. 7A is a diagram illustrating a state when the upper cover is maintained at the exposure position, and FIG. 7B is a diagram illustrating a state when the upper cover is moved to the standby position. In the figure, 217 is a protrusion, 218 is a moving plate, 219 is a spring, 220 is a lever, and 231 is a guide groove.

  A protrusion 217 is provided on the upper right side of the upper cover 216. The image forming apparatus also includes a moving plate 218 having a guide groove 231 that engages with the protrusion 217 of the upper cover 216. The moving plate 218 is attached so as to be movable back and forth within the image forming apparatus 100. The moving direction of the moving plate 218 is a direction orthogonal to the sliding movement direction of the upper cover 216 shown in FIGS.

A lever 220 is connected to the front side of the moving plate 218. The front end of the lever 220 is located inside the front door 111 shown in FIG. 6, and when the front door 111 is closed, it abuts against the inner wall surface of the front door 111, as shown in FIG. The position is displaced to the back side of the device. Here, the guide groove 231 of the moving plate 218 is provided obliquely with respect to the moving direction of the moving plate 218. At the position shown in FIG. 7A, the protrusion 217 is displaced to the left by the action of the guide groove 231. ing. As a result, the upper cover 216 is also displaced to the left and maintained at the exposure position shown in FIG.
That is, in a normal state in which the front door 111 is closed, the irradiation window 212 provided in the upper cover 216 is maintained on the optical path of each light beam for exposing the photosensitive drum 3, and the photosensitive drum by the exposure unit 1 is used. 3 exposure (that is, printing) is possible.

When the front door 111 is opened, the pressure on the lever 220 shown in FIG. 7A is released. Here, a spring 219 is attached to the lever 220, and the moving plate 218 is biased in a direction to be displaced forward. Thereby, when the front door 111 is opened and the pressing force to the lever 220 by the inner wall surface is released, the moving plate 218 is displaced forward by the urging force of the spring 219. As a result, the protrusion 217 engaged with the guide groove 231 moves to the right, and the upper cover 216 also moves to the right to enter the standby state shown in FIG. At this position, the optical path of the light beam is shielded by the wall portion of the upper cover 216, and each irradiation window 212 is displaced laterally away from the optical path.
In this state, an operator or the like can insert the cleaning member from the opening portion of the front door 111 and clean the irradiation window 212. At this position, it is possible to avoid contamination due to the toner falling when the developing device 2 and the photosensitive drum 3 are replaced.

It is a figure which shows the structural example of the image forming apparatus provided with the laser exposure apparatus by this invention. It is a figure which shows the structural example of the secondary optical system of a laser exposure apparatus. It is a figure which shows the structural example of the secondary optical system of a laser exposure apparatus. It is a figure which shows the other structural example of the secondary optical system of a laser exposure apparatus. It is a figure which shows the other structural example of the secondary optical system of a laser exposure apparatus. It is another figure which shows the structural example of the image forming apparatus provided with the laser exposure apparatus by this invention. FIG. 6 is a schematic diagram for specifically explaining the configuration of an interlocking mechanism that slides the upper cover shown in FIGS. 4 and 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Exposure unit, 2 ... Developing device, 3 ... Photosensitive drum, 4 ... Cleaner unit, 5 ... Charger, 6 ... Intermediate transfer belt unit, 7 ... Fixing unit, 8 ... Diameter, 10 ... Transfer roller, 11a, 11b ... Pickup roller, 12a, 12b, 12c, 12d ... Conveyance roller, 13 ... Registration roller, 61 ... Intermediate transfer belt, 62 ... Intermediate transfer belt drive roller, 63 ... Intermediate transfer belt driven roller, 64 ... Intermediate transfer roller, 65 ... Intermediate transfer belt cleaning unit 71 ... heat roller 72 ... pressure roller 73 ... external heating belt 81 ... paper feed cassette 82 ... paper feed cassette 91 ... paper discharge tray 92 ... document placement table 100 ... image Forming apparatus, 110 ... apparatus main body, 111 ... front door, 120 ... document processing apparatus, 201 ... polygon mirror, 202 ... lens, 2 DESCRIPTION OF SYMBOLS 3 ... Cylindrical lens, 204 ... 1st mirror for Y, 204 ... 1st mirror for Y, 206 ... Mirror for K, 207 ... Mirror for C, 208 ... 2nd mirror for C, 209 ... 1st mirror for M, 210 DESCRIPTION OF SYMBOLS Mirror 211 211 Case 212 Irradiation window 213 Shielding projection 214 214 Guide rail 215 Cleaning brush 216 Top cover 217 Projection 218 Moving plate 219 Spring 220 Lever 221 ... Driver, 222 ... Solenoid, 223 ... Rotation fulcrum, 224 ... Spring, 225 ... Rotation arm, 231 ... Guide groove.

Claims (9)

In a laser emitting unit that emits a laser beam, and a laser exposure apparatus that scans the laser beam emitted from the laser emitting unit and exposes an external photoconductor to write a latent image on the photoconductor,
A housing in which the optical components of the laser exposure apparatus are arranged;
A cover that is attached to the housing and shields optical components disposed inside the housing from outside air;
The cover includes an irradiation window that transmits laser light to be emitted to the outside, and is between an exposure position where the laser light is transmitted through the irradiation window and emitted to the outside, and a standby position that shields the optical path of the laser light. A laser exposure apparatus characterized by being movable with   2. The laser exposure apparatus according to claim 1, wherein the cover includes a plurality of the irradiation windows.   3. The laser exposure apparatus according to claim 1, wherein the cover prevents toner for visualizing a latent image written on the photosensitive member from moving to the irradiation window in the vicinity of the irradiation window. 4. A laser exposure apparatus comprising a shielding protrusion.   The laser exposure apparatus according to claim 1, further comprising a cleaning member for cleaning the irradiation window in the vicinity of the irradiation window.   An image forming apparatus comprising: the laser exposure apparatus according to claim 1; and a photoconductor, wherein the laser exposure apparatus forms a latent image on the photoconductor and visualizes the latent image. An image forming apparatus.   6. The image forming apparatus according to claim 5, further comprising a moving unit for moving the cover and a control unit for controlling the moving unit, wherein the control unit energizes the moving unit during an image forming operation, and An image forming apparatus, wherein the cover is moved from the standby position to the exposure position.   6. The image forming apparatus according to claim 5, wherein the cleaning member is in contact with the irradiation window at the standby position.   8. The image forming apparatus according to claim 7, wherein the cleaning member is slidably held on the irradiation window at the standby position.   6. The image forming apparatus according to claim 5, wherein a part of the casing constituting the image forming apparatus is configured to be openable and closable, and the opening and closing of a part of the casing constituting the image forming apparatus is linked to the movement of the cover. An image forming apparatus comprising an interlocking mechanism for causing the image forming apparatus to operate.

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